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| L298 thermal pad connection |
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| ricko_uk:
Hi, the datasheet for the L298 ( https://www.sparkfun.com/datasheets/Robotics/L298_H_Bridge.pdf ) shows the pad for the Multiwatt package shows that the tab is connected to ground but the same datasheet does not say anything about the thermal pad of the PowerSo version. For lower impedance and for routing purposes I would prefer to connect it to ground but not sure if I should do that. I was going to test it with a meter but then thought that even if the meter shows continuity, the silicon inside might not be designed to support high current going to the pad and might fuse. Does anybody know if it should be left unconnected? Thank you |
| wraper:
--- Quote from: ricko_uk on June 12, 2020, 02:14:12 am ---I was going to test it with a meter but then thought that even if the meter shows continuity, the silicon inside might not be designed to support high current going to the pad and might fuse. Does anybody know if it should be left unconnected? --- End quote --- It will not pass much current if resistance is higher than through the pins. Should be safe to connect to GND. As die should be the same, it should be connected to the pad the same way as to the tab in multiwatt. Tab is not necessarily connected to the GND pin though. Also you may want connect it to GND mostly not because of routing but because you can use the whole ground plane as a heatsink. But I don't suggest to use this IC to begin with. There are better more modern alternatives with MOSFET output stage which have lower losses/heat dissipation and on top of that often are less expensive. |
| Doctorandus_P:
I've got some memory that pad's like these (usually?) can be connected to the voltage rail which the datasheet says it's connected to, but it should not be relied upon to pass much current. That was for a completely other chip though, where the tab was connected to the positive or negative voltage rails. It may have been for the LM3886. Also: L298 is an obsolete chip that just refuses to die. Biggest problem is you loose a few Volt for the high current motor connections. For about the same price you can get similar chips with MOS-Fets that have a low enough Rds-on to not need a significant heat sink at all, because they just pass (almost) all voltage to the motor. These usually only need a bit of connected copper on the PCB for heat dissipation. |
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